2mas: Difference between revisions
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[[Image:2mas.gif|left|200px]]<br /><applet load="2mas" size=" | [[Image:2mas.gif|left|200px]]<br /><applet load="2mas" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="2mas, resolution 2.3Å" /> | caption="2mas, resolution 2.3Å" /> | ||
'''PURINE NUCLEOSIDE HYDROLASE WITH A TRANSITION STATE INHIBITOR'''<br /> | '''PURINE NUCLEOSIDE HYDROLASE WITH A TRANSITION STATE INHIBITOR'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
2MAS is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Crithidia_fasciculata Crithidia fasciculata] with CA and PIR as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Purine_nucleosidase Purine nucleosidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.2.1 3.2.2.1] Known structural/functional Sites: <scene name='pdbsite=S1:Description Not Provided'>S1</scene>, <scene name='pdbsite=S2:Description Not Provided'>S2</scene>, <scene name='pdbsite=S3:Description Not Provided'>S3</scene> and <scene name='pdbsite=S4:Description Not Provided'>S4</scene>. Full crystallographic information is available from [http:// | 2MAS is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Crithidia_fasciculata Crithidia fasciculata] with <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=PIR:'>PIR</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Purine_nucleosidase Purine nucleosidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.2.1 3.2.2.1] Known structural/functional Sites: <scene name='pdbsite=S1:Description+Not+Provided'>S1</scene>, <scene name='pdbsite=S2:Description+Not+Provided'>S2</scene>, <scene name='pdbsite=S3:Description+Not+Provided'>S3</scene> and <scene name='pdbsite=S4:Description+Not+Provided'>S4</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2MAS OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: uridine]] | [[Category: uridine]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Feb 3 10:46:31 2008'' | ||
Revision as of 11:46, 3 February 2008
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PURINE NUCLEOSIDE HYDROLASE WITH A TRANSITION STATE INHIBITOR
OverviewOverview
Nucleoside N-ribohydrolases are targets for disruption of purine salvage, in the protozoan parasites. The structure of a trypanosomal, N-ribohydrolase in complex with a transition-state inhibitor is reported, at 2.3 A resolution. The nonspecific nucleoside hydrolase from Crithidia, fasciculata cocrystallized with p-aminophenyliminoribitol reveals tightly, bound Ca2+ as a catalytic site ligand. The complex with the, transition-state inhibitor is characterized by (1) large protein, conformational changes to create a hydrophobic leaving group site (2), C3'-exo geometry for the inhibitor, typical of a ribooxocarbenium ion (3), stabilization of the ribooxocarbenium analogue between the neighboring, group 5'-hydroxyl and bidentate hydrogen bonds to Asn168; and (4), octacoordinate Ca2+ orients a catalytic site water and is liganded to two, hydroxyls of the inhibitor. The mechanism is ribooxocarbenium, stabilization with weak leaving group activation and is a departure from, glucohydrolases which use paired carboxylates to achieve the transition, state.
About this StructureAbout this Structure
2MAS is a Single protein structure of sequence from Crithidia fasciculata with and as ligands. Active as Purine nucleosidase, with EC number 3.2.2.1 Known structural/functional Sites: , , and . Full crystallographic information is available from OCA.
ReferenceReference
Trypanosomal nucleoside hydrolase. A novel mechanism from the structure with a transition-state inhibitor., Degano M, Almo SC, Sacchettini JC, Schramm VL, Biochemistry. 1998 May 5;37(18):6277-85. PMID:9572842
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